Running multiple pipe strings in cased wells



Aug. 1, 1961 W. M. o'Rl-:ILLY 2,994,382

RUNNING MULTIPLE PIPE STRINGS IN CASED WELLS Filed July 20, 1959 FIG. 3.

FIG. I.

INVENTOR.

WALLACE M. O'R EILLY,

ATloRNEY.

United States PatentOce 2,994,382 g y Patented Aug. 1, 196i 2,994,382 RUNNING MULTIPLE PIPE STRINGS IN CASED WELLS Wallace M. OReilly, Midland, Tex., assignor, "by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed July 20, 1959, Ser. No. 828,341 3 Claims. (Cl. 166-243) This invention relates to apparatus for use in completing a cased well containing a multiplicity of tubing strings, and more particularly to apparatus for preventing a plurality of tubing strings from becoming entangled when they are lowered into the same cased well.

Often it is desirable to produce a plurality of hydrocarbon-containing earth formations through a single borehole that penetrates the formations. The economic advantages of such an arrangement are obvious inasmuch as the expensive drilling of a multiplicity of boreholes is obviated.

In order to produce the formations it is necessary to lower a plurality of tubing strings into the borehole. However, it has been found that the separate tubing strings tend to inten-weave and bind with various degrees of tightness. At times it becomes extremely ditiicult, if not impossible, to lower a second tubing string to desired depth.

In accordance with the teachings of the present invention, the first tubing string to be lowered into a well is provided with a plurality of elongated, fairly narrow spring members that are aixed at one end to the first tubing string and that extend downwardly and away from the tubing string in a spiral that substantially follows the inner circumference of the casing within which the first tubing string is lowered. The spring member may be extended in a loop and set screws utilized to make the physical connection. The pipe string will be urged into engagement with the casing, and a second tubing string may then be lowered into the well within the spiral spring member without the possibility of the two tubing strings becoming entangled. To facilitate lowering the second tubing string into the cased Well, the tubing string may be provided with collars having tapered ends.

The invention will be described in greater detail with reference to the accompanying drawings, wherein:

FIG. l is a vertical sectional View of an oil or gas well showing the elements comprising the invention positioned therein;

FIG. 2 is a sectional View taken along section 2f-2 of FIG. 1; and

FIG. 3 is an isometric view of the spring or guide element shown in FIG. l.

With reference now to FIG. 1, there is shown a pair of tubing strings 3 and 5 positioned within the casing 1 of an oil or gas well. rl`he casing is shown as having been cemented to the surrounding earth formations. Tubing string 3 comprises a multiplicity of sections which are connected together by conventional collar means; two of the collar means are designated by reference numeral 9. Connected to selected ones of the collar means are a plurality of exible guide members 7; the details of construction of the guide members are shown most perspicuously in FIGS. 2 and 3. The guide members may be spaced apart between 30 to 90 feet on the tubing string. Connection between the guide members and the collars of the tubing string 3 may be made by forming the upper portion of the guide members into a closed loop and welding the loop closed so that set screws 13 may make the physical connection between the tubings or the collar.

The exible spring guide member 7 extends downwardly and away from tubing string 3 in a spiral having a diameter somewhat less than the diameter of the casing 1, but shaped to provide positive contact with the tubing string 5 as the tubing string is lowered into the hole. The distance between the guide member and the casing should be less than the diameter of the tubing to be lowered into the well. The size of the spring member will vary according to the tubular goods employed. The spring member for two strings of 2% inch O.D'. tubing in 7 inch O.D. casing may be between l and 3 feet long. It may be constructed of any desirable alloy metal such as spring steel in dimensions of approximately l to 3 inches in width and ls to 3% inch in thickness. In speci-lic well 4conditions such as Where corrosion may cause extreme deterioration of ordinary materials, the composition of the spring member may be altered accordingly and nickel or chromium steel alloys may be employed or even materials not of an iron base, such as aluminum bronze, may be used. The angle that the spinal portion of the spring guide member makes with the horizontal should be between 30 and 60 degrees.

The apparatus shown in FIG. l is assembled by first lowering pipe string 3 into the casing. The flexible spring guide members 7 are properly oriented relative to preceding guide members using techniques such as are well known in the art of directional drilling to orient whipstocks and then aflixed either to the collars or to the tubing sections as the pipe string is made up while it is being run .into the casing. After the first pipe string has been lowered into the casing to the desired depth, the second pipe string 5 may be lowered. Pipe string 5 will pass through the aligned spiral loops of guide members 7 without becoming entangled with pipe string 3. Should the lower end of pipe string 5 engage a guide member 7, the lower end of the pipe will slide along the downwardly spiraling guide member until it slips over the inner upper edge of the guide member. After both pipe strings have been lowered to desired depth, conventional additional completion techniques may be followed. As mentioned above, the collar sections of pipe string 5 may be tapered to facilitate passage of pipe string 5 past the flexible guide members 7.

Under certain circumstances it may be desirable to remove the flexible spring guide members 7 without removing .the pipe strings from the casing. If this circumstance is anticipated, the spring guide members may be formed of aluminumI and may be dissolved by circulating a suitable inhibited acid, such as hydrochloric acid, or a suitable caustic agent through one of the pipe strings and up through the annulus of the casing.

The invention is not necessarily to be restricted to the specific structural details or arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of the invention.

What is claimed is:

1. Apparatus for use in dual-completing a well comprising: a casing in the well, a first pipe string extending into the casing including a plurality of tubular pipe sections connected .together by coupling members; a plurality of elongated spring guide members each affixed at one end thereof to said pipe string and spirally extending downwardly and away from said pipe string in a spiral having a diameter slightly less than the diameter of the casing so as to tend to bias said pipe string against the casing, said guide members being in oriented alignment to guide a second tubular pipe string as it is lowered into the hole.

2. The combination of claim l whereinthe elongated spring guide member includes a closed loop at its upper end aflixed to the second pipe section by set screws.

3. Apparatus for use in dual-completing a well cornprising: a casing in the well; a lirst pipe string extending References Cited in the le of this patent UNITED STATES PATENTS Hoadley Apr. l0, 1888 Olson n Mar. 1S, 1913 Matthews Mar. l, 19.21 Klein Aug. 6, 1940 lClapp May 30, 1950 Schoonmaken' et al. Feb. 5,v 1952 Wengen et al Mar. 17, 1953 

